Manipulation of phonon transport is the key to optimizing the overall energy conversion efficiency of thermoelectric materials. In this work, we demonstrate that the antibonding hybridization resulting from elemental substitution can weaken the interatomic interactions, which in turn enhances the structural anharmonicity and hinders the heat conduction of layered ABTe 3 (ABSe 3 ) (A = Al, Ga, In, As, and Sb; B = Si and Ge) compounds. It is revealed that the filled antibonded p-d state of GaSiTe 3 (GaSiSe 3 ) originates from the mixture of Ga-3d and Te-5p (Se-4p) orbitals, whereas the outer As-s electrons hybridize with the Te (Se)-p electrons to form antibonding states in AsSiTe 3 (AsSiSe 3 ). Consequently, the room temperature lattice thermal conductivity (κ L ) of AlGeTe 3 (AlGeSe 3 ) is reduced from 3.27 (3.86) W/mK to 0.62 (1.47) W/mK for GaSiTe 3 (GaSiSe 3 ) and 1.91 (1.74) W/mK for AsSiTe 3 (AsSiSe 3 ) in spite of their similar atomic masses and crystal structures. Based on these findings, we propose candidates of InGeTe 3 and SbGeTe 3 to realize potentially high thermoelectric performance by rationally incorporating heavy weight elements but still maintaining weak atomic binding interactions. Due to the low κ L of 0.26 (0.6) W/mK, a high n-type (p-type) ZT value of 2.18 (1.08) at 750 (650) K is finally captured in InGeTe 3 (SbGeTe 3 ). Our results not only provide insights to understand the relationship between chemical bonding and lattice thermal conductivity but also offer an approach to design and discover materials with expected thermal transport and thermoelectric properties.

The use of heterojunctions is a promising solution to the problem of crosssensitivity in gas sensors. In this work, a carbon monoxide sensor based on the CuO/TiO 2 heterojunction was designed and fabricated. Due to the good adsorption properties of CuO materials to CO, and the heterojunction interface charge transfer, the CuO/TiO 2 thin film sensor exhibits high sensitivity to CO at room temperature. The response is as high as 10.8-200 ppm CO, about 10 times its response to H 2 . Interference from H 2 is greatly reduced by optimizing the structure of the CuO/TiO 2 heterojunction. This reliable detection of carbon monoxide with excellent discrimination against H 2 is of great significance for the development of CO gas sensors.

Identifying approaches that reduce thermal conductivity with little impact on electrical transport performance remains a central challenge for the thermoelectric community. Here, we use density functional theory calculations to demonstrate that K 2 CdX (XSn, Pb), with a crystal structure composed of a one-dimensional zigzag Cd-X chain sublattice and an isolated alkali metal K atom, exhibits favorable electronic and phonon transport as well as superior thermoelectric conversion efficiency. We reveal that the presence of a long-range ionic bond and multiple band characteristics lead to "electron crystal"-like electrical transport performance. On the other hand, the ultralow lattice thermal conductivity (κ L ) of the K 2 CdX compound mainly originates from the strong structural anharmonicity, which is caused by a lowdimensional sublattice combined with the heterogeneity of a weak chemical bond and the rattling vibration of K atoms in a crystal matrix. As a result, high average carrier mobility (>20 cm 2 V −1 S −1 ), low lattice thermal conductivity below 0.4 W/mK, and spectacularly high average zT larger than 2.0 predicted for the K 2 CdPb system highlight the direction for identifying compounds with potential thermoelectric performance in this crystal family. KEYWORDS: K 2 CdPb (K 2 CdSn) crystal, 1D zigzag atomic chain, rattlerlike K atoms, anisotropic electrical and thermal transport, thermoelectric performance, first-principles calculations, Boltzmann transport theory

Development of metal oxide semiconductors‐based methane sensors with good response and low power consumption is one of the major challenges to realize the real‐time monitoring of methane leakage. In this work, a self‐assembled mulberry‐like ZnO/SnO2 hierarchical structure is constructed by a two‐step hydrothermal method. The resultant sensor works at room temperature with excellent response of ~56.1% to 2000 ppm CH4 at 55% relative humidity. It is found that the strain induced at the ZnO/SnO2 interface greatly enhances the piezoelectric polarization on the ZnO surface and that the band bending results in the accumulation of chemically adsorbed ions close to the interface, leading to significant improvement in the sensing performance of the methane gas sensor at room temperature.

Low electronic conductivity and large volume changes during the (de)lithiation process are the two main challenges for ZnO anode materials used for lithium‐ion batteries (LIB). Here, a free‐standing, flexible, and binder‐free LIB electrode composed of ZnO nanorods and carbon cloth (CC) is fabricated. This is then decorated with Ag nanoparticles and finally coated by an amorphous carbon layer to form the hybrid electrode: (C@(Ag&ZnO)). The voids among the nanorods are sufficient to accommodate the volume expansion of the ZnO while the flexible CC, which acts as the current collector, relieves the volume change‐induced stress. The Ag nanoparticles are effective in improving the conductivity. This composite electrode shows excellent LIB performance with a stable long cycling life over 500 cycles with a reversible capacity of 1093 mAh g−1 at a current density of 200 mA g−1. It also shows good rate performance with reversible capacity of 517 mAh g−1 under a high‐current density of 5000 mA g−1. In situ Raman spectroscopy is conducted to investigate the contributions of the amorphous carbon layer to the capacity of the whole electrode and the synergy between the CC and ZnO nanorods.